#include "Stack.h"

void StackInit(ST* ps)
{
	assert(ps);
	ps->a = (STDataType*)malloc(sizeof(STDataType) * 4);
	ps->capacity = 4;
	ps->top = 0;
}

void StackDestory(ST* ps)
{
	assert(ps);
	free(ps->a);
	ps->a = NULL;
}

void StackPush(ST* ps, STDataType x)
{
	assert(ps);
	if (ps->capacity == ps->top)
	{
		STDataType* tmp = (STDataType*)realloc(ps->a, sizeof(STDataType) * 2);
		if (tmp == NULL)
		{
			printf("realloc fail");
		}
		else
		{
			ps->a = tmp;
			ps->capacity *= 2;
		}
	}

	ps->a[ps->top] = x;
	ps->top++;
}

void StackPop(ST* ps)
{
	assert(ps);
	assert(ps->top > 0);
	ps->top--;
}

STDataType StackTop(ST* ps)
{
	assert(ps);
	assert(ps->top > 0);
	return ps->a[ps->top - 1];
}

int StackSize(ST* ps)
{
	assert(ps);
	return ps->top;
}

bool StackEmpty(ST* ps)
{
	assert(ps);
	return ps->top == 0;
}